Apparatus for producing a three-dimensional object by laser sintering

Abstract

An apparatus for producing a three-dimensional object by successive solidification of layers of a solidifiable material (7) at places corresponding to the respective cross-section of the object by means of radiation is provided whereby the apparatus comprises a support (4) for supporting the object (6) to be formed, a coating device (12) for applying layers of the solidifiable material (7) onto the support (4) or a previously solidified layer, a solidifying device (14) for solidifying the layers of the material (7) at places corresponding to the respective cross-section of the object and a heating apparatus (8) disposed above the support (4) in operational position for heating the solidifiable material (7), the heating apparatus (8) comprising at least one straight radiant heater (81) with a varying heating power along its length.

We claim: 
     
       1. An apparatus for producing a three-dimensional object by successive solidification of layers of a solidifiable material at places of said layers, which correspond to a respective cross-section of said object, using electro-magnetic radiation, said apparatus comprising: supporting means for supporting said object;   coating means for applying a layer of said solidifiable material onto said supporting means or onto a previously solidified layer;   solidifying means for solidifying said layer of said material; and   heating means for heating said layer of said material, said heating means being disposed above said supporting means and comprising a plurality of straight radiant heaters each having a length, a center region, two opposite end regions and a heating capacity which varies over said length, said heating capacity being greater at said end regions than at said center region,   whereby said radiant heaters are arranged to form a closed polygon.   
     
     
       2. The apparatus of claim 1, further comprising means for adjusting the elevation of said supporting means and a working field defined by said layer of said material applied to said supporting means or to a previously solidified layer. 
     
     
       3. The apparatus of claim 1, comprising a square working field having four sides and comprising four radiant heaters of equal length, said radiant heaters being arranged in a square form parallel to the respective sides of said working field in a predetermined distance therefrom. 
     
     
       4. The apparatus of claim 1, comprising a rectangular working field having four sides and comprising four radiant heaters arranged in a rectangular form parallel to the respective sides of said working field with a predetermined distance therefrom. 
     
     
       5. The apparatus of claim 1, further comprising means for adjusting the distance of said heating means from said layer. 
     
     
       6. The apparatus of claim 1, wherein said radiant heater comprises an infrared radiator. 
     
     
       7. The apparatus of claim 6, further comprising a control means for controlling said heating means and a sensor for measuring the temperature of said layer of said applied material. 
     
     
       8. The apparatus of claim 7, wherein said sensor comprises a non-contacting temperature sensor. 
     
     
       9. The apparatus of claim 7, wherein said control means comprises a PID-controller. 
     
     
       10. The apparatus of claim 7, wherein said control means comprises a PI-controller. 
     
     
       11. The apparatus of claim 1, wherein said layer of said material defines a working field and said radiant heater irradiates said working field with a predetermined angle, said apparatus further comprising means for adjusting said angle. 
     
     
       12. The apparatus of claim 1, comprising a rectangular working field having four sides and comprising four radiant heaters arranged in a rectangular form with a predetermined distance therefrom. 
     
     
       13. An apparatus for producing a three-dimensional object by successive solidification of layers of a solidifiable material at places of said layers, which correspond to a respective cross-section of said object, using electro-magnetic radiation, said apparatus comprising: supporting means for supporting said object;   coating means for applying a layer of said solidifiable material onto said supporting means or onto a previously solidified layer;   solidifying means for solidifying said layer of said material; and   heating means for heating said layer of said material, said heating means being disposed above said supporting means and comprising a plurality of straight radiant heaters each having a length, a center region, two opposite end regions and a heating capacity which varies over said length, said heating capacity being greater at said end regions than at said center region,   wherein said radiant heater comprises two heating resistors each disposed at a respective one of said end regions.   
     
     
       14. The apparatus of claim 13, wherein said radiant heater further comprises a third heating resistor extending over said entire length of said radiant heater. 
     
     
       15. The apparatus of claim 14, wherein said radiant heater comprises two parallel channels each receiving a corresponding heating coil, one of said heating coils being a divided coil and the other coil being a continuous coil.